Drug development

• Microorganisms and plants have been evolving for millions of years and along the way they've evolved to produce a range of substances that are able to do all sorts of things including killing pathogens
• Instead of having to develop all of our drugs from scratch we've been able to take these substances from them and either use them directly as medicines or sometimes modify them in a lab of it first and then use them as medicines
• Substances taken from nature and used as medicines

  • Aspirin (from willow tree bark)
  • Digitalis (from foxglove plants)
  • Penicillin (from Penicillium fungus)
• Efficacy


  How well the drug works, e.g. how good is an antibiotic at killing bacteria or how well does a pain relief medication reduce your pain
• Toxicity


  How harmful the drug is, e.g. does it damage our cells or have any side effects
• Dosage


  How much of the drug or what concentration of the drug should be given
• Drug testing stages


  1. Testing on human cells and tissues (pre-clinical)

  2. Testing on live animals (pre-clinical)

  3. Clinical testing on healthy volunteers (starting with low dose)

  4. Clinical testing on people with the target illness (finding optimum dosage)
• Clinical trials


  • Blind (volunteers don't know if they have real drug or placebo)
  • Double-blind (neither volunteers nor doctors know who has real drug)
• The purpose of blind and double-blind trials is to avoid any unconscious bias
• Peer review, where the drug testing is analyzed by other scientists, is central to all of science and helps to prevent false claims or results from getting published